The present invention relates to data communications between a truck tractor and a cargo trailer, and more specifically to techniques for remotely determining and managing their connection.
Mobile asset management is a major concern in various transportation industries such as trucking, railroad and rental cars. In the trucking industry, an asset manager needs to keep track of the status and location of each tractor and cargo trailer in a fleet. The fleet asset manager should also know whether each trailer is in service (i.e., already in use being transported by a tractor) or out of service (i.e., not being transported by a tractor at the present time). The asset manager should have similar information with respect to whether each tractor in a fleet is hauling a trailer or not, and thus whether it is available for service. The fleet asset manager should also be able to monitor the progress of each tractor and trailer according to a predefined plan, for scheduling purposes.
One difficult aspect of asset management concerns the availability and status of cargo trailers. Although empty trailers are often numerous and widely available, they are nomadic, can be scattered across a wide territory, and it is often difficult to know their specific status with certainty. Automated trailer tracking systems, such as described in U.S. Pat. No. 6,529,529 assigned to Terion, Inc., the assignee of the present invention, greatly enhance capabilities for fleet management. These systems typically include various sensors and communication units located on the tractor and trailer. The sensors can be used to determine the status and location of a trailer, check for proper operating conditions, determine any misuse, and monitor the progress of each tractor and its associated coupled trailer for scheduling and security purposes.
Automated tracking systems have become quite popular, as they allow transportation carriers and shippers to better manage their assets. However, one aspect that is not well tracked is the connection of a trailer to a specific tractor or type of tractor.
In the typical scenario, it is the sole responsibility of the driver to identify and communicate tractor/trailer connect and disconnect events to fleet managers via the asset management system. Unfortunately, the human driver can make mistakes, in occasionally picking up the wrong trailer, or in communicating the trailer identification number incorrectly. Such methods also do not address scenarios when someone intent on compromising a trailer or its cargo simply commits an outright theft of a trailer.
In certain other electronic systems used on trucks, status information for a trailer may be communicated to a tractor. See for example, U.S. Pat. No. 6,799,814 which describes a system wherein an Anti-lock Braking System (ABS) produces a data signal. The ABS data signal is then sent to the tractor using a Power Line Carrier (PLC) type communication bus. In this manner, the status of a subsystem such as the status of the braking system may be displayed or may otherwise made available to the driver.